Alert archive / Alabama / Tornado Watches in 2006

Tornado Watch 91

March 13, 200617 counties in Alabama; 9 counties in Georgia

The Storm Prediction Center issued this tornado watch at Mar 13, 2006, 5:56 PM CST for 17 counties in Alabama; 9 counties in Georgia. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Mar 13, 2006, 5:56 PM CST (23:56 UTC)
Expired
Mar 13, 2006, 10:10 PM CST
In force
4 hr
Issued by
the Storm Prediction Center
All 26 counties

Bibb County, AL, Blount County, AL, Calhoun County, AL, Cherokee County, AL, Chilton County, AL, Clay County, AL, Cleburne County, AL, Coosa County, AL, DeKalb County, AL, Etowah County, AL, Jackson County, AL, Jefferson County, AL, Marshall County, AL, Perry County, AL, Shelby County, AL, St. Clair County, AL, Talladega County, AL, Catoosa County, GA, Chattooga County, GA, Dade County, GA, Floyd County, GA, Gordon County, GA, Murray County, GA, Polk County, GA, Walker County, GA, Whitfield County, GA

The radar

The Northeast Alabama radar (KHTX), 89 km from the middle of the area, began a volume at 23:58 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

Warnings issued inside it

8 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Mar 13, 6:01 PM CSTTornado WarningBMXBlount44 min
Mar 13, 6:36 PM CSTTornado WarningBMXJefferson54 min
Mar 13, 6:42 PM CSTTornado WarningBMXBlount, Etowah, St. Clair63 min
Mar 13, 7:26 PM CSTTornado WarningBMXJefferson40 min
Mar 13, 7:42 PM CSTTornado WarningBMXCalhoun, Cherokee, Etowah35 min
Mar 13, 7:54 PM CSTTornado WarningBMXSt. Clair29 min
Mar 13, 8:14 PM CSTSevere Thunderstorm WarningBMXBibb20 min
Mar 13, 8:18 PM CSTSevere Thunderstorm WarningBMXJefferson16 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Birmingham, AL (KBMX), launched 12:00Z, 11.9 hours before the alert went out and 125 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Birmingham, AL at 12:00Z on 2006-03-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 37 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Birmingham, AL at 12:00Z on 2006-03-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 60 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
37 J/kg
Mixed-layer CIN
-28 J/kg
Mixed-layer LCL
552 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
60 m²/s²
0-3 km storm-relative helicity
138 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
WWUS20 KWNS 132357
SEL1  
SPC WW 132357
ALZ000-GAZ000-140500-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 91
NWS STORM PREDICTION CENTER NORMAN OK
555 PM CST MON MAR 13 2006

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF 

       CENTRAL AND NORTHEAST ALABAMA
       EXTREME NORTHWEST GEORGIA

EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 555 PM UNTIL 1100
PM CST.

TORNADOES...HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 40 STATUTE MILES
EAST AND WEST OF A LINE FROM 45 MILES NORTH OF ROME GEORGIA TO 15
MILES EAST SOUTHEAST OF CENTREVILLE ALABAMA.  FOR A COMPLETE
DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE
(WOUS64 KWNS WOU1).

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA.
PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING
WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE
WARNINGS.

OTHER WATCH INFORMATION...CONTINUE...WW 88...WW 89...WW 90...

DISCUSSION...ONGOING SUPERCELLS ACROSS N CENTRAL AND NW AL SHOULD
CONTINUE EWD TOWARD CENTRAL/NE AL THE NEXT FEW HOURS.  THOUGH THE
BOUNDARY LAYER WILL GRADUALLY COOL WITH THE LOSS OF SURFACE
HEATING...SOME INCREASE IN LOW-LEVEL MOISTURE WITH TIME WILL DELAY
SURFACE STABILIZATION. EXPECT VERTICAL SHEAR AND INSTABILITY TO
REMAIN SUFFICIENT FOR SUPERCELLS CAPABLE OF PRODUCING A COUPLE OF
TORNADOES...ALONG WITH DAMAGING WINDS AND SOME HAIL FOR THE NEXT FEW
HOURS.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
450. MEAN STORM MOTION VECTOR 26030.


...THOMPSON

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 13, 12:36 PM CSTMesoscale DiscussionSPCColbert, Fayette, Franklin, Lamar, Lauderdale, Lawrence and 6 more114 min
Mar 13, 1:48 PM CSTTornado WatchSPCColbert, Cullman, Fayette, Franklin, Greene, Hale and 12 more6 hr
Mar 13, 3:32 PM CSTMesoscale DiscussionSPCChoctaw, Clarke, Marengo, Monroe, Washington, Wilcox88 min
Mar 13, 3:59 PM CSTMesoscale DiscussionSPCBlount, Colbert, Cullman, Fayette, Franklin, Jackson and 13 more91 min
Mar 13, 5:41 PM CSTMesoscale DiscussionSPCBibb, Blount, Calhoun, Cherokee, Clay, Cleburne and 25 more64 min

Nearby

Tornado Watches in Alabama, 2006Tornado Watches in Georgia, 2006Every tornado watch in 2006

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.